1. Textbook Readability and Reading Ability of Science Students;Belden, Bernard;The Science Teacher,April, 1962
2. Readability of Biology Textbooks and the Reading Ability of Biology Students;Belden;School Science and Mathematics,December, 1961
3. An Investigation of Two Methods of Measuring the Reading Difficulty of Materials for Elementary Science;Herrington;Science Education,December, 1958
4. The Readability of High School Science Texts.;Mallinson;The Science Teacher,November 1951
5. The Reading Difficulty of Textbooks for High School Biology.;Mallinson;The American Biology Teacher,November, 1950